hex prefix the sig so we don't need to re-sign every time

[glitch003]

When working with session sigs, i noticed we seem to re-sign stuff everytime, with this error below. I think it's just because the signature isn't hex prefixed. This PR should fix this by upgrading us to use the verify() function and hex prefixing the signature.

validate() has been deprecated, please update your code to use verify(). validate() may be removed in future versions.
Error: signature missing v and recoveryParam (argument="signature", value="3782d0a8c088bfd8e071593d9b0002df8cb2aa4258e639d708ad70041652e478282f60a019bbd3e69bf09831f8b2df2dcfdf220fe050e2280de2a6ef8588a8961c", code=INVALID_ARGUMENT, version=bytes/5.7.0)
    at Logger.makeError (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/logger/lib/index.js:238:21)
    at Logger.throwError (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/logger/lib/index.js:247:20)
    at Logger.throwArgumentError (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/logger/lib/index.js:250:21)
    at splitSignature (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/bytes/lib/index.js:359:24)
    at recoverPublicKey (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/signing-key/lib/index.js:59:42)
    at recoverAddress (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/transactions/lib/index.js:72:62)
    at verifyMessage (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/@ethersproject/wallet/lib/index.js:241:46)
    at /Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/siwe/dist/client.js:241:61
    at new Promise (<anonymous>)
    at SiweMessage.<anonymous> (/Users/chris/Documents/WorkStuff/Lit/pkp-capacity-credit-delegator/node_modules/siwe/dist/client.js:160:20) {
  reason: 'signature missing v and recoveryParam',
  code: 'INVALID_ARGUMENT',
  argument: 'signature',
  value: '3782d0a8c088bfd8e071593d9b0002df8cb2aa4258e639d708ad70041652e478282f60a019bbd3e69bf09831f8b2df2dcfdf220fe050e2280de2a6ef8588a8961c'
}
Need retry because verify failed SiweError {
  type: 'Signature does not match address of the message.',
  expected: undefined,
  received: 'Resolved address to be 0x6250BdbeF65c05Cb14F5AEE3A261Ba3E29dD69Da'
}